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<FONT color="green">001</FONT>    // Copyright 2008 Waterken Inc. under the terms of the MIT X license<a name="line.1"></a>
<FONT color="green">002</FONT>    // found at http://www.opensource.org/licenses/mit-license.html<a name="line.2"></a>
<FONT color="green">003</FONT>    package org.waterken.syntax.json;<a name="line.3"></a>
<FONT color="green">004</FONT>    <a name="line.4"></a>
<FONT color="green">005</FONT>    import java.io.EOFException;<a name="line.5"></a>
<FONT color="green">006</FONT>    import java.io.IOException;<a name="line.6"></a>
<FONT color="green">007</FONT>    import java.io.Reader;<a name="line.7"></a>
<FONT color="green">008</FONT>    <a name="line.8"></a>
<FONT color="green">009</FONT>    import org.waterken.syntax.SourceReader;<a name="line.9"></a>
<FONT color="green">010</FONT>    <a name="line.10"></a>
<FONT color="green">011</FONT>    /**<a name="line.11"></a>
<FONT color="green">012</FONT>     * A JSON token reader.<a name="line.12"></a>
<FONT color="green">013</FONT>     */<a name="line.13"></a>
<FONT color="green">014</FONT>    public final class<a name="line.14"></a>
<FONT color="green">015</FONT>    JSONLexer {<a name="line.15"></a>
<FONT color="green">016</FONT>        private final SourceReader s;<a name="line.16"></a>
<FONT color="green">017</FONT>        private       int line;<a name="line.17"></a>
<FONT color="green">018</FONT>        private       int column;<a name="line.18"></a>
<FONT color="green">019</FONT>        private       String head;<a name="line.19"></a>
<FONT color="green">020</FONT>        <a name="line.20"></a>
<FONT color="green">021</FONT>        /**<a name="line.21"></a>
<FONT color="green">022</FONT>         * Constructs an instance.<a name="line.22"></a>
<FONT color="green">023</FONT>         * @param in    UTF-8 input stream<a name="line.23"></a>
<FONT color="green">024</FONT>         */<a name="line.24"></a>
<FONT color="green">025</FONT>        public<a name="line.25"></a>
<FONT color="green">026</FONT>        JSONLexer(final Reader in) {<a name="line.26"></a>
<FONT color="green">027</FONT>            s = new SourceReader(in);<a name="line.27"></a>
<FONT color="green">028</FONT>            line = s.getLine();<a name="line.28"></a>
<FONT color="green">029</FONT>            column = s.getColumn();<a name="line.29"></a>
<FONT color="green">030</FONT>            head = "";              // empty token indicates start of token stream<a name="line.30"></a>
<FONT color="green">031</FONT>        }<a name="line.31"></a>
<FONT color="green">032</FONT>        <a name="line.32"></a>
<FONT color="green">033</FONT>        // org.waterken.syntax.json.JSONLexer interface<a name="line.33"></a>
<FONT color="green">034</FONT>        <a name="line.34"></a>
<FONT color="green">035</FONT>        /**<a name="line.35"></a>
<FONT color="green">036</FONT>         * Gets the line number of the {@linkplain #getHead head} token.<a name="line.36"></a>
<FONT color="green">037</FONT>         */<a name="line.37"></a>
<FONT color="green">038</FONT>        public int<a name="line.38"></a>
<FONT color="green">039</FONT>        getLine() { return line; }<a name="line.39"></a>
<FONT color="green">040</FONT>        <a name="line.40"></a>
<FONT color="green">041</FONT>        /**<a name="line.41"></a>
<FONT color="green">042</FONT>         * Gets the column number of the {@linkplain #getHead head} token.<a name="line.42"></a>
<FONT color="green">043</FONT>         */<a name="line.43"></a>
<FONT color="green">044</FONT>        public int<a name="line.44"></a>
<FONT color="green">045</FONT>        getColumn() { return column; }<a name="line.45"></a>
<FONT color="green">046</FONT>        <a name="line.46"></a>
<FONT color="green">047</FONT>        /**<a name="line.47"></a>
<FONT color="green">048</FONT>         * Gets the most recently {@linkplain #next read} token.<a name="line.48"></a>
<FONT color="green">049</FONT>         * @return most recent token, or {@code null} if EOF<a name="line.49"></a>
<FONT color="green">050</FONT>         */<a name="line.50"></a>
<FONT color="green">051</FONT>        public String<a name="line.51"></a>
<FONT color="green">052</FONT>        getHead() { return head; }<a name="line.52"></a>
<FONT color="green">053</FONT>        <a name="line.53"></a>
<FONT color="green">054</FONT>        /**<a name="line.54"></a>
<FONT color="green">055</FONT>         * Move to the next token in the input stream.<a name="line.55"></a>
<FONT color="green">056</FONT>         * @return newly read token<a name="line.56"></a>
<FONT color="green">057</FONT>         * @throws EOFException EOF<a name="line.57"></a>
<FONT color="green">058</FONT>         * @throws IOException  any I/O error<a name="line.58"></a>
<FONT color="green">059</FONT>         * @throws Exception    invalid character escape<a name="line.59"></a>
<FONT color="green">060</FONT>         */<a name="line.60"></a>
<FONT color="green">061</FONT>        public String<a name="line.61"></a>
<FONT color="green">062</FONT>        next() throws EOFException, IOException, Exception {<a name="line.62"></a>
<FONT color="green">063</FONT>            final int c = skipWhitespace(s);<a name="line.63"></a>
<FONT color="green">064</FONT>            line = s.getLine();<a name="line.64"></a>
<FONT color="green">065</FONT>            column = s.getColumn();<a name="line.65"></a>
<FONT color="green">066</FONT>            switch (c) {<a name="line.66"></a>
<FONT color="green">067</FONT>            case -1:<a name="line.67"></a>
<FONT color="green">068</FONT>                head = null;<a name="line.68"></a>
<FONT color="green">069</FONT>                throw new EOFException();<a name="line.69"></a>
<FONT color="green">070</FONT>            case ',':<a name="line.70"></a>
<FONT color="green">071</FONT>                head = ",";<a name="line.71"></a>
<FONT color="green">072</FONT>                s.read();<a name="line.72"></a>
<FONT color="green">073</FONT>                break;<a name="line.73"></a>
<FONT color="green">074</FONT>            case '{':<a name="line.74"></a>
<FONT color="green">075</FONT>                head = "{";<a name="line.75"></a>
<FONT color="green">076</FONT>                s.read();<a name="line.76"></a>
<FONT color="green">077</FONT>                break;<a name="line.77"></a>
<FONT color="green">078</FONT>            case ':':<a name="line.78"></a>
<FONT color="green">079</FONT>                head = ":";<a name="line.79"></a>
<FONT color="green">080</FONT>                s.read();<a name="line.80"></a>
<FONT color="green">081</FONT>                break;<a name="line.81"></a>
<FONT color="green">082</FONT>            case '}':<a name="line.82"></a>
<FONT color="green">083</FONT>                head = "}";<a name="line.83"></a>
<FONT color="green">084</FONT>                s.read();<a name="line.84"></a>
<FONT color="green">085</FONT>                break;<a name="line.85"></a>
<FONT color="green">086</FONT>            case '[':<a name="line.86"></a>
<FONT color="green">087</FONT>                head = "[";<a name="line.87"></a>
<FONT color="green">088</FONT>                s.read();<a name="line.88"></a>
<FONT color="green">089</FONT>                break;<a name="line.89"></a>
<FONT color="green">090</FONT>            case ']':<a name="line.90"></a>
<FONT color="green">091</FONT>                head = "]";<a name="line.91"></a>
<FONT color="green">092</FONT>                s.read();<a name="line.92"></a>
<FONT color="green">093</FONT>                break;<a name="line.93"></a>
<FONT color="green">094</FONT>            case '\"':<a name="line.94"></a>
<FONT color="green">095</FONT>                head = readString(s);<a name="line.95"></a>
<FONT color="green">096</FONT>                break;<a name="line.96"></a>
<FONT color="green">097</FONT>            default:<a name="line.97"></a>
<FONT color="green">098</FONT>                head = readKeyword(s);<a name="line.98"></a>
<FONT color="green">099</FONT>            }<a name="line.99"></a>
<FONT color="green">100</FONT>            return head;<a name="line.100"></a>
<FONT color="green">101</FONT>        }<a name="line.101"></a>
<FONT color="green">102</FONT>        <a name="line.102"></a>
<FONT color="green">103</FONT>        public void<a name="line.103"></a>
<FONT color="green">104</FONT>        close() throws IOException {<a name="line.104"></a>
<FONT color="green">105</FONT>            final int c = skipWhitespace(s);<a name="line.105"></a>
<FONT color="green">106</FONT>            line = s.getLine();<a name="line.106"></a>
<FONT color="green">107</FONT>            column = s.getColumn();<a name="line.107"></a>
<FONT color="green">108</FONT>            s.close();<a name="line.108"></a>
<FONT color="green">109</FONT>            if (-1 != c) { throw new IllegalStateException(); }<a name="line.109"></a>
<FONT color="green">110</FONT>        }<a name="line.110"></a>
<FONT color="green">111</FONT>        <a name="line.111"></a>
<FONT color="green">112</FONT>        // rest of implementation consists of static helper functions<a name="line.112"></a>
<FONT color="green">113</FONT>        <a name="line.113"></a>
<FONT color="green">114</FONT>        static private final String whitespace = " \t" + SourceReader.newLine;<a name="line.114"></a>
<FONT color="green">115</FONT>        <a name="line.115"></a>
<FONT color="green">116</FONT>        static private int<a name="line.116"></a>
<FONT color="green">117</FONT>        skipWhitespace(final SourceReader s) throws IOException {<a name="line.117"></a>
<FONT color="green">118</FONT>            int c = s.getHead();<a name="line.118"></a>
<FONT color="green">119</FONT>            while (whitespace.indexOf(c) != -1) {<a name="line.119"></a>
<FONT color="green">120</FONT>                c = s.read();<a name="line.120"></a>
<FONT color="green">121</FONT>            }<a name="line.121"></a>
<FONT color="green">122</FONT>            return c;<a name="line.122"></a>
<FONT color="green">123</FONT>        }<a name="line.123"></a>
<FONT color="green">124</FONT>        <a name="line.124"></a>
<FONT color="green">125</FONT>        static private final String delimiter = whitespace + ",{:}[]\"";<a name="line.125"></a>
<FONT color="green">126</FONT>        <a name="line.126"></a>
<FONT color="green">127</FONT>        static private String<a name="line.127"></a>
<FONT color="green">128</FONT>        readKeyword(final SourceReader s) throws IOException {<a name="line.128"></a>
<FONT color="green">129</FONT>            final StringBuilder r = new StringBuilder();<a name="line.129"></a>
<FONT color="green">130</FONT>            int c = s.getHead();<a name="line.130"></a>
<FONT color="green">131</FONT>            do {<a name="line.131"></a>
<FONT color="green">132</FONT>                r.append((char)c);<a name="line.132"></a>
<FONT color="green">133</FONT>                c = s.read();<a name="line.133"></a>
<FONT color="green">134</FONT>            } while (-1 != c &amp;&amp; delimiter.indexOf(c) == -1);<a name="line.134"></a>
<FONT color="green">135</FONT>            return r.toString();<a name="line.135"></a>
<FONT color="green">136</FONT>        }<a name="line.136"></a>
<FONT color="green">137</FONT>        <a name="line.137"></a>
<FONT color="green">138</FONT>        static private String<a name="line.138"></a>
<FONT color="green">139</FONT>        readString(final SourceReader s) throws Exception {<a name="line.139"></a>
<FONT color="green">140</FONT>            final StringBuilder r = new StringBuilder();<a name="line.140"></a>
<FONT color="green">141</FONT>            r.append((char)s.getHead());<a name="line.141"></a>
<FONT color="green">142</FONT>            while (true) {<a name="line.142"></a>
<FONT color="green">143</FONT>                final int c = s.read();<a name="line.143"></a>
<FONT color="green">144</FONT>                if ('\\' == c) {<a name="line.144"></a>
<FONT color="green">145</FONT>                    r.append(readEscape(s));<a name="line.145"></a>
<FONT color="green">146</FONT>                } else {<a name="line.146"></a>
<FONT color="green">147</FONT>                    r.append((char)c);<a name="line.147"></a>
<FONT color="green">148</FONT>                    if ('\"' == c) {<a name="line.148"></a>
<FONT color="green">149</FONT>                        s.read();<a name="line.149"></a>
<FONT color="green">150</FONT>                        return r.toString();<a name="line.150"></a>
<FONT color="green">151</FONT>                    }<a name="line.151"></a>
<FONT color="green">152</FONT>                }<a name="line.152"></a>
<FONT color="green">153</FONT>            }<a name="line.153"></a>
<FONT color="green">154</FONT>        }<a name="line.154"></a>
<FONT color="green">155</FONT>        <a name="line.155"></a>
<FONT color="green">156</FONT>        static private char<a name="line.156"></a>
<FONT color="green">157</FONT>        readEscape(final SourceReader s) throws Exception {<a name="line.157"></a>
<FONT color="green">158</FONT>            switch (s.read()) {<a name="line.158"></a>
<FONT color="green">159</FONT>            case '\"': return '\"';<a name="line.159"></a>
<FONT color="green">160</FONT>            case '\\': return '\\';<a name="line.160"></a>
<FONT color="green">161</FONT>            case '/': return '/';<a name="line.161"></a>
<FONT color="green">162</FONT>            case 'b': return '\b';<a name="line.162"></a>
<FONT color="green">163</FONT>            case 'f': return '\f';<a name="line.163"></a>
<FONT color="green">164</FONT>            case 'n': return '\n';<a name="line.164"></a>
<FONT color="green">165</FONT>            case 'r': return '\r';<a name="line.165"></a>
<FONT color="green">166</FONT>            case 't': return '\t';<a name="line.166"></a>
<FONT color="green">167</FONT>            case 'u': return readUnicodeEscape(s);<a name="line.167"></a>
<FONT color="green">168</FONT>            default: throw new Exception("0x" + Integer.toHexString(s.getHead()));<a name="line.168"></a>
<FONT color="green">169</FONT>            }<a name="line.169"></a>
<FONT color="green">170</FONT>        }<a name="line.170"></a>
<FONT color="green">171</FONT>        <a name="line.171"></a>
<FONT color="green">172</FONT>        static private char<a name="line.172"></a>
<FONT color="green">173</FONT>        readUnicodeEscape(final SourceReader s) throws Exception {<a name="line.173"></a>
<FONT color="green">174</FONT>            return (char)((hex(s.read()) &lt;&lt; 12) |<a name="line.174"></a>
<FONT color="green">175</FONT>                          (hex(s.read()) &lt;&lt;  8) |<a name="line.175"></a>
<FONT color="green">176</FONT>                          (hex(s.read()) &lt;&lt;  4) |<a name="line.176"></a>
<FONT color="green">177</FONT>                          (hex(s.read())      ) );<a name="line.177"></a>
<FONT color="green">178</FONT>        }<a name="line.178"></a>
<FONT color="green">179</FONT>        <a name="line.179"></a>
<FONT color="green">180</FONT>        static private int<a name="line.180"></a>
<FONT color="green">181</FONT>        hex(final int c) throws Exception {<a name="line.181"></a>
<FONT color="green">182</FONT>            if ('0' &lt;= c &amp;&amp; '9' &gt;= c) {        return c - '0'     ; }<a name="line.182"></a>
<FONT color="green">183</FONT>            else if ('A' &lt;= c &amp;&amp; 'F' &gt;= c) {   return c - 'A' + 10; }<a name="line.183"></a>
<FONT color="green">184</FONT>            else if ('a' &lt;= c &amp;&amp; 'f' &gt;= c) {   return c - 'a' + 10; }<a name="line.184"></a>
<FONT color="green">185</FONT>            else { throw new Exception("0x" + Integer.toHexString(c)); }<a name="line.185"></a>
<FONT color="green">186</FONT>        }<a name="line.186"></a>
<FONT color="green">187</FONT>    }<a name="line.187"></a>




























































</PRE>
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